12 papers
Tracking real-space quantum state breathing through Floquet-projector geometry
Arpit Raj, Johannes Mitscherling, Björn Trauzettel
Periodic driving of spatially periodic quantum systems generates band structures that are absent in static crystals. We present a quantum geometric theory to characterize the Floqu…
Multi-field oscillons/I-balls in the Friedberg-Lee-Sirlin model
Kai Murai, Tatsuya Ogawa, Fuminobu Takahashi
We study oscillon/I-ball solutions in a real scalar version of the Friedberg-Lee-Sirlin (FLS) model. Using the multiple-scale analysis, we derive the conditions for oscillon soluti…
Resolving the QCD Axion Domain Wall Problem with a Light Axion
Junseok Lee, Kai Murai, Fuminobu Takahashi +1
We propose two novel solutions to the domain wall problem of the QCD axion by introducing a massless or light axion that also couples to gluons. The first solution applies when the…
Dynamical Prevention of Topological Defect Formation
Junseok Lee, Kai Murai, Kazunori Nakayama +1
Topological defects can have significant cosmological consequences, so their production must be examined carefully. It is usually assumed that topological defects are produced if t…
Why ? Anthropic Selection in a + Axion Dark Energy Model
Kai Murai, Fuminobu Takahashi
We study a dark energy model composed of a bare negative cosmological constant and a single ultra-light axion, motivated by the string axiverse. Assuming that intelligent observers…
Sign-Flipping Axion Potentials via Kapitza-Type Modulation by Heavy Axions
Kai Murai, Fuminobu Takahashi, Kosei Tomiyama
We show that the potential of a light axion can flip sign, or even nearly vanish, as a result of coherent oscillations of a heavier axion with which it mixes. This phenomenon is an…